Plant Operation

Energy and chemicals are the two major resources that we consumed in our plants. The conservation of energy will be discussed under the "Progress of Clean Air Charter" in the next section. Chemicals are used in sewage treatment to facilitate the removal of suspended solids and tiny organic particles. The chemical enhanced primary treatment at the Stonecutters Island Sewage Treatment Works is a typical example. Chemicals are also used for odour control and sludge dewatering.

Mindful of the escalating demand for chemicals, DSD continued the chemical audit in 2007. The findings of the audits at the Cyberport STW and Shek Wu Hui STW indicated that alum could be saved by 25% and sodium hydroxide by 30%, respectively. There was an increase in the use of ferric chloride and a decrease in the use of alum in 2007. This was a result of using ferric chloride to replace alum in the Siu Ho Wan STW for odour control.

Green Office

DSD offices are green. We continue our efforts in conservation of resources in our offices. We set our room temperature at 25.5 C, use recycled paper and recycle printer cartridges and fluorescent lamps. Our environmental inspection teams check and remind staff to turn off the computers and the peripheral devices when they are not in use. The lighting intensity in our offices are reduced to save energy, but adjusted to sufficient level to suit individual requirement. On the use of paper, we further reduced the consumption in 2007 by 9% from 15,437 reams to 14,046 reams, in which 96% was recycled paper. Two campaigns to promote staff awareness on environmental protection were held in 2007, one aimed at green slogan, and the other encouraged creativity in converting unwanted materials for household or office use.

Paper Consumption and Recycling